president obama working on keeping his answers concise. mitt romney, his aides say, is getting used to the one-on-one format, with the race so tight, anything could happen and so much could ride on tomorrow night. mitt romney held a rally in denver overnight, where he previewed tomorrow night's fireworks. >> these debates are an opportunity for each of us to describe the pathway forward for america that we would choose. and the american people have to make their choice as to what kind of america they want. >> reporter: he will likely start the day tomorrow with a workout. he's an elliptical machine kind of guy. meanwhile, the president is at this posh resort in nevada where he'll no doubt also be hitting the gym before getting another day of debate practice. while he may be strong physically, he admits he's out of debate shape. romney debated most recently in february. >> i think the earmarks, we had it with them. >> reporter: the last time the president debated was almost four years ago. >> we've got to have a president who is going to ta